Help: Chatter on lathe, what's wrong

Discussion in 'Tools' started by Mac McCaskie, Aug 11, 2019.

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  1. Aug 11, 2019 #1

    Mac McCaskie

    Mac McCaskie

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    I have just started practicing on my Grizzly 9 x 22 lathe and get chatter when I'm turning, but not facing. In the photo I have a 2" steel cylinder, the end is good when faceing, but shows chatter when I tried to use a parting tool, also marks from the tool bit (the picture shows the second tool bit I tried). What things can I try to stop the chatter.

    Details, I have not done anything else on this lathe, so it's essentially brand new.
    the cylinder is about 2" x 6", facing on the end went fine. When turning the chatter stops about 1.5" from the chuck and runs fine (what you see is the results of a frustrated newbie cleaning up with a file). With the parting and cutter tools, I tried a little above and below center but didn't notice any change. Oh, I varied speeds from 100 rpm to 450 rpm.

    One last tidbit, I wonder if I damaged the "power head" IMG_0252[1].JPG . My first attempt was a total goof. I started up the lathe with this steel but the chuck was not tight. After I got it stopped, the chuck jaws were bent after the cylinder whacked the tool post. I replaced the chuck with a new replacement from Grizzly, checked level, re-adjusted gibs and inspected the tool post.
     
  2. Aug 11, 2019 #2

    dnalot

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    Lucky something bad didn't happen. A piece of material that long needs to be supported by a center at the end you faced. Go to you-tube and watch some videos on basic use of a metal lathe. A lathe can mess you up if your not very careful.
     
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  3. Aug 12, 2019 #3

    Ghosty

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    Also the tool is the wrong shape for the direction you are machining, it is ground for machining from the headstock to the tailstock.
     
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  4. Aug 12, 2019 #4

    coulsea

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    As Ghosty said your tool doesn't look right. I would recommend that any newbie invest in a tangential tool holder, they are a good allrounder and foolproof to sharpen, it takes one of the problems away so you can concentrate on all the other things that you may be doing wrong.

     
  5. Aug 12, 2019 #5

    Mac McCaskie

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    Thanks for the replies.
    Hum, I did not think the piece was too long, but I suppose I should start smaller. I didn't hear any comments that something is wrong with the lathe, so that's a plus.
     
  6. Aug 12, 2019 #6

    Tim1974

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    Very general rule is if the length is more than 3 x dia use the tail stock for support or the steady if you have it for face work . Honestly you where very lucky there that you didn’t have it rip out of the chuck !
     
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  7. Aug 12, 2019 #7

    deeferdog

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    Hi Mac. At the very least you are at risk of losing some body parts if you keep this up. Find someone with a bit of experience to show you a few basics and some of the fundamental safety rules of lathe operation. Take it one step at a time and it will soon become second nature and with the basics in hand the whole world of home hobby machining will open up. We really want to keep you as a member with all your members. Cheers, Peter
     
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  8. Aug 12, 2019 #8

    comstock-friend

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    On YouTube, you may see someone like Adam (Abom79) work a piece like yours without tailstock support, but he has a real industrial type lathe that is MUCH more solid than your Grizzly. We have to be much more concerned about support with our smaller hobby lathes...
     
  9. Aug 12, 2019 #9

    packrat

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    Quote {I tried a little above and below center but didn't notice any change} Your tool needs to be dead center to the work,
    try and chuck up a shorter peace of round stock say about 2 inches long. You will need a good right hand cutting tool. For that longer stock you will need a center drill and a center..
    If you need a good right hand tool let me know and I will send you one..
     
    Last edited: Aug 12, 2019
  10. Aug 12, 2019 #10

    Shopgeezer

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    From one newbie to another, invest a lot of time watching You Tube videos. There are lots of excellent basic videos as well as series from old hands like Tubal Cain and others. Lots of tips and tricks to show you how to use the lathe and mill. I also had a One inch piece of steel come loose because of the beginners mistake of not getting the workpiece centred properly in the 3 jaws and tightened it only on 2 of the jaws. It whacked the tool post and pushed the tool bit down (diamond tool holder) like it was supposed to. Scared the heck out of me. I’ve caught myself leaving the key in the chuck a few times. Fortunately the lathe won’t start with the chuck cover raised. Good safety feature.

    And a word about metals. Cold rolled steel is miserable stuff to machine. It leaves a very rough surface with an HSS tool. I have carbide bits too and they are no better. When I took a machining course the instructor brought “stress proof “ steel for us to use. As I understand it this steel has a higher lead content than normal to improve machining. My local metals vendor says they used to have a grade 1144 that was machinable but it is not available. They now stock grade 1045 for machining. It costs $3.00/inch for 2” round stock. All the different grades and alloys of metals (and their numbers) are still a mystery to me. The cost of new metal is incredibly high. I spend a lot of time searching through scrap yards. But you never know what you are getting there.
     
  11. Aug 12, 2019 #11

    Shaun free

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    You have a lot going on there and all of them will contribute to chatter.

    As mentioned a work work piece is usually ok to not be supported 3x the diameter of the stock your using. So 1" round stock can hang out around 3". This is a good rule for heavier machines and you may find your grizzly will chatter. The material your cutting and what the cutter material is also contributes. Personally I support the work most of the time to keep away from the springboard effect.

    How sharp your cutter is will also be a factor and cutter shape. Steel uses a different shape than aluminium.

    You mentioned parting but I did not see a parting bit. This is very important, NEVER part pieces between centers, its not pretty if you try. The parting tool must be sharp, I sharpen the parting tool every time I pick it up to use it. this only takes minutes and I got tired of scraping hours of work.

    Google machinist feeds and speeds and go off those numbers. This will give you a good guide to what speed to spin the work piece. I use this for mild steel. RPM=SFMx4/ Diameter of the rotating item ( cutter or work). Lets say a HHS bit with mild steel .5" bar stock. My chart calls for 60-100 SFM I will start with 75 RPM=75x4/.5 RPM=600. This is for a large engine lathe. I would think if you looked through the booklet from Grizzly you will find a chart for your machine.
     
  12. Aug 12, 2019 #12

    larryg

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  13. Aug 12, 2019 #13

    packrat

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    photo of right hand tool cutting to the chuck..You do not need a carbide tool, but you get the idea of tool angle..
     

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    Last edited: Aug 12, 2019
  14. Aug 12, 2019 #14

    John Antliff

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    Most, if not all metal turning lathes, will develop chatter at some point depending on parameters like the stickout length relative to the diameter of the job, the speed of rotation, the sharpness and form of the tool, the rigidity of the setup (lathe bed/head bearings/saddle looseness etc.), the depth of cut, the feed rate, the tool height, the power available and the basic harmonic frequency of the machine tool. When you get all these parameters just right the result is usually a good surface finish and chips that come off without undue noise or heat i.e. if the chip is blue then you are probably close to the maximum metal removal rate that your machine can handle. As you can see from that list nearly everything about lathe turning will contribute to "chatter"!

    If you get chatter and the tool is set up correctly and sharp and the turning speed and feed are nominal then try a different speed preferably, but not always, a lower one. This will alter the frequency generated and avoid the fundamental harmonic frequency of the lathe from building up to a disturbing effect. Reducing the feed and/or depth of cut can also be beneficial.

    I would suggest that as a novice you try turning some softer materials first like aluminium or brass to get your initial experience of setting up and turning to a dimension. Lots of practice needed before competency will accrue! The internet is a wonderful place to learn, as are some books i.e. The Amateur's Workshop by Ian Bradley ISBN 1-85486-130-1 Argus Books 1976.

    My first lathe was a pre-war Patrick which could theoretically turn a piece of metal 6 inches in diameter however it was of such lightweight construction that it barely managed to turn successfully steel at 2 inches in diameter. The headstock bearings and bed/shears were just not beefy enough to handle anything bigger. I had to be patient with it and only take very light cuts if I wanted a good finish and dimensional accuracy.

    Hope that all helps - don't get discouraged by your first interactions with what is generally considered to be the best tool in the workshop - it really will earn it's keep and last a lifetime if looked after.
     
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  15. Aug 13, 2019 #15

    Mark Duquette

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    This is F E Read turning prehardened 4140. A too deep of a cut can deflect the cutter or the material and will eventually spring back resulting in chatter.

    DSC00308.JPG
     
  16. Aug 13, 2019 #16

    Bill Lawson

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    All of the above advice is sound. After you have a rigid setup, your speed may be too high or feedrate may not be high enough
     
  17. Aug 13, 2019 #17

    Moper361

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  18. Aug 13, 2019 #18

    Moper361

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    I would recomend these for anyone not just newbie. I made my own and a set for my father who is well over 80 years old .He has used nothing else since he wished he had them 60 od years ago .
     
  19. Aug 13, 2019 #19

    IanN

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    Hi,

    Regarding tangential cutting tools, there is loads of information out there in old text books.

    The tangential tool form has been in common use for at least 200 years - see

    https://taths.org.uk/tools-trades/articles/88-heel-tools-an-experiment-with-old-methods

    Remember that tool forms used over 100 years ago were often optimised for use on machines powered by foot treadle - ie low power and low rigidity

    Second point - register for a course in machine work at your local college, or join your local model engineering club. You will learn more in an hour with an experienced machinist looking over your shoulder than in a whole year of "trial and error"

    I'm a bit bias in my opinions - I teach engineering apprentices for a living, so I would always recommend live interaction with experienced people over a video.

    Finally, remember that (in the UK) the apprenticeship to become a qualified machinist takes five years of full time practical experience in industry and theoretical study at college - a total of about 10,000 hours. If you devote 5 hours a week to your hobby, then in 40 years, you will have the same experience as a newly qualified apprentice.....

    All the best,
    Ian
     
  20. Aug 13, 2019 #20

    coulsea

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    lots of good advice from everyone. reading through them reminds me of what I think are the things that I would tell a newbie.
    1 sharpen tools often, practice makes perfect
    2 use your live centre as often as you can. even facing off 2 inches go in as far as you can without hitting the centre and then remove it to finish off the centre. the centre forces are a lot less than the outside. most things end up with a hole down the middle anyway
    3 for the first few months or maybe years only use the parting tool on brass or aluminium preferably less that 1 inch with a hole up the middle of half the diameter. otherwise you will break things and get too scared to ever use it again.
    4 your lathe and tools are not indestructible, be gentle. if it doesn't fit through the centre of your chuck it needs extra thought.
    5 you and your machine can not do the things that youtube can. they can part off like a hot knife through butter.
     

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